If you can work out a way to boost your muscle
glycogen to supra-normal levels, your performances in athletic events lasting
longer than about 60 minutes will be much improved. Glycogen is a key fuel
during such exertions, but a basic problem is that, unlike fat, glycogen cannot
be stored in your body in relatively limitless amounts. In addition, the
glycogen in your muscles is quite rapidly depleted during fairly intense
exercise, so that muscles begin to notice a shortage of glycogen after 60-90
minutes of activity. Yes, they can call on fat to provide fuel for further
contractions and force production, but fat supports a lower intensity of
exercise, and thus movement speed drops. This is why athletes who do a poor job
of muscular glycogen replenishment before lengthy workouts, games or races
usually slow down after 60 minutes, while their glycogen-loaded counterparts
continue to work at the same intensity. So, the key question is: how do you
make sure that you are amply glycogen-loaded? Once it became clear in the 1960s
that glycogen was especially important during exercise lasting longer than an
hour, Swedish scientists began to work at a furious pace to answer this
question. A Swede named Ahlborg developed a protocol in which athletes
performed a bout of very strenuous exercise and then consumed a
high-carbohydrate diet for a period of three days while training normally (1).
It worked! Athletes in the Ahlborg study boosted muscle glycogen above 150
mmol.kg-1 wet weight (normal levels are about 80-120).

There was just one problem, though  that
strenuous bout of exercise. Usually, athletes want to be especially
glycogen-loaded for a big race, and the notion of carrying out a very strenuous
exertion lasting longer than an hour just three days before a big competition
(in order to stimulate high rates of glycogen synthesis) was troublesome. Such
efforts could interfere with tapering and could produce wear and tear on
muscles which were frantically trying to heal themselves before a major event.
Another problem also became apparent: athletes sometimes overloaded themselves
during their three-day carb-fests. Instead of feeling unusually energetic, they
ended up being bloated and sluggish on race day. The Ahlborg plan just
wouldnt do! Ahlborgs colleague, a fellow Swede named Bergstrom,
developed a slightly different plan. Bergstrom advised athletes to first engage
in a rugged bout of strenuous exercise, then consume a high-fat,
low-carbohydrate diet for three days (to really drive glycogen levels down),
then undertake strenuous exercise again (just to make sure that muscle-glycogen
levels were really low), and finally feast on carbohydrates for the seemingly
magical period of three days, while training very lightly. This technique also
succeeded in magnifying muscle glycogen concentrations.

The perils of strenuous exercise bouts before
a major event

Again there were problems, however. Specifically,
Bergie had failed to take into account the fact that two bouts of very
strenuous, glycogen-depleting exercise during the week before a very important
competition might be a bad idea. In addition, the three initial days of
high-fat, low-carb eating left athletes irritable and less than
super-confident. Finally, the three-day carbohydrate festival at the end of the
Bergstrom protocol again left many athletes feeling gigantic and slow, rather
than sleek and fast. Mike Sherman of Ohio State entered these troubled waters
in the early 1980s with a very sensible and seemingly more practical plan for
glycogen loading.

Addressing the paradox of recommending strenuous
exercise during the week before a major event, Shermans stratagem called
for no heavy exertion, and in fact allowed decreasing amounts of exercise on
consecutive days. In Shermans six-day plan, athletes ingested a routine,
mixed (modest carbohydrate content) diet for three days and then
stoked up on carbs for the next three days. Like the techniques developed by
Ahlborg and Bergstrom, the Sherman stratagem worked, producing
muscle glycogen levels above 150 mmol.kg-1 wet weight. However, the overall
plan once again left many athletes feeling sluggish, and many individuals did
not particularly want to cut back on training uniformly and relentlessly during
their tapering periods, preferring to alternate days of doing almost nothing
with days of performing modest amounts of quality work. In addition, many
athletes wisely questioned the necessity of the initial three days of
mixed-diet eating, and so Shermans plan was modified to consist of just
the three days of high-carb eating, accompanied by successively lighter
workouts.

Unafraid to enter this controversy, my own US
newsletter Running Research News has for the past 10 years been recommending
routine high-carbohydrate consumption (in the form of about four grams of
carbohydrate per pound of body weight per day) for endurance athletes. This
recommendation is based on research carried out by Clyde Williams and
colleagues at Loughborough University, showing that endurance athletes engaged
in serious training who consume less carbohydrate than this often end up
gradually depleting their muscle glycogen stores, leading to lower-quality
workouts and poorer performances. Our position has been that, if this strategy
leads to routinely high levels of muscle glycogen, there is no special need to
try to ram more carbs home shortly before races and extreme workouts. The
reduced training employed in these times will allow extra glycogen synthesis to
occur in muscles, and the chronically carb-rich diet will furnish the carbs
necessary to get the job done.

Admittedly, though, the RRN plan is not without
its own perils: for one thing, 4g of carbohydrate per pound of body weight per
day has been shown to be a bit rich for some athletes, especially those who
have previously restricted their calorie and carb intake. These athletes, many
of whom may routinely take in just 2g per pound per day (we have even
documented one quite successful athlete who was trying to get by with 1g!), may
gain weight and feel extremely lethargic if they make a quantum leap to our
ideal of 4g/lb/day.

So whats the answer? Is there a simple,
quick way to maximise muscle glycogen levels without fuss, extended periods of
unusual eating or disruption of normal training?

In a word, yes! Thanks to research carried out at
the Department of Human Movement and Exercise Science at the University of
Western Australia, we now have such a plan (4). This plan takes just a day, and
it produces incredibly high muscle glycogen levels!

Intensity and glycogen synthesis

The Western Australia work pivots around one key
concept: very high intensities of exercise actually stimulate higher rates of
muscle glycogen synthesis than moderate intensities of exercise carried out for
prolonged periods. Naturally, athletes have been a little afraid to engage in
very high-intensity exercise during their tapering, glycogen-loading periods,
but the Australian researchers asked, quite reasonably: what if the intense
exercise is just long enough to dramatically kick-start glycogen synthesis
 but not so long as to interfere with tapering and recovery? In their
ingenious plan, the Australians settled on a very short duration of intense
exercise  just three minutes! Could such a brief period of exertion carry
the broad load of heavy carbohydrate loading on its apparently puny shoulders?
To find out, the Australians worked with seven healthy, endurance-trained male
subjects. The athletes averaged 22 years of age, trained about 10 hours per
week, possessed max aerobic capacities of around 56 ml.kg-1.min-1, and normally
consumed about 6.6 grams of carbohydrate per kg of lean body mass per day (e.g.
3g of carbs per pound of lean body mass per day and 2.55g of carbs per pound of
body weight per day).

Such intakes of carbs are fairly routine among
endurance athletes, and thus the Australians had created a nice test of whether
their one-day plan could really dramatically bolster muscle glycogen contents
in typical athletes. On the morning the one-day high-carb diet commenced, the
athletes had muscle biopsies performed on their quadriceps muscles (to assess
glycogen levels), carried out a five-minute warm-up on a cycle ergometer, and
then blasted through a sustained 150-second sprint on the ergometer at a very
high intensity of 130% VO2max. At the end of this sprint, the athletes 
without a second of hesitation  embarked on an all-out 30s sprint.
Lactate levels at the end of this three-minute period of intense work soared to
21.9 mM/litre!

When carbo windows are open widest

Following a cool-down, each subject began the
24-hour high-carb eating plan, during which they ingested 12g of relatively
high-glycaemic-index carbs per kg of lean body mass (e.g. 5.45g per pound of
lean body mass and 4.6g per pound of body weight, just above the RRN
recommendation). Crucially, the ingestion of carbohydrate was initiated within
20 minutes of the end of the exercise. (Remember that your muscles carbo
windows are open widest shortly after a bout of exercise ends; by
two hours-or-so after exercise, they are open just a crack.) The participants
ate high-carb foods they liked, including pasta, bread and rice but they also
poured in extra carbohydrate in the form of the maltodextrose-rich drink
Polycose, produced by Ross Laboratories in Columbus, Ohio. Indeed, about 80% of
the carbs ingested over the 24-hour period came from this drink. The energy
ingested as fat and protein, by contrast, was marginal  less than 10% of
the caloric total for the day.

On the morning after the exercise and initiation
of the carbo-loading regime, a second quadriceps muscle biopsy was taken. This
revealed incredibly high levels of muscle glycogen; the mean glycogen
concentration in the quads, which had been just 109 mmol.kg-1 wet weight before
the trial, soared to 198.2  an 82-% increase  afterwards! Analysis
revealed that both slow and fast-twitch muscle fibres did an equally fantastic
job of storing super concentrations of glycogen. The Australian plan was a real
winner! It is the fastest glycogen-loading plan ever reported in the scientific
literature. It also produces end glycogen concentrations (~198 mmol.kg-1 wet
weight) which are extraordinarily high  considerably higher than the
131-153 readings often reported after three or even six days of traditional
carbo-loading.

Preventing dips in muscle glycogen

The Australian research has several practical
implications. If you are training strenuously, you need to worry about
preventing dips in your day-to-day muscle glycogen levels. One way to do that
is to routinely consume a high-carb diet, but another strategy  based on
the Australian findings  would be to add in about three minutes of
intense exercise near the end of many of your easy-to-moderate-intensity
workouts. Such short periods of high-intensity work should not increase your
risk of injury or burn-out, should enhance your fitness and should kick-start
the post-workout glycogen-synthesis process, helping to ensure that you will
have enough glycogen in your muscles for the next days workout. Of
course, if your workout is already intense, there is no need to add anything to
it.

This recommendation to slip in three minutes of
intense stuff near the end of an easy workout may seem a bit bizarre, but it
may well prove to be an exceedingly good strategy. Bear in mind that after
fairly prolonged exercise consisting of only moderate-intensity work, it
usually takes about 24 hours for muscle glycogen stores to return to
pre-exercise levels, even when a high-carb diet is followed (6). The true
glycogen-loading following such exercise does not really occur until the second
and third days afterwards. By contrast, with the Aussie three-minute plan,
super-loading occurs within the first 24 hours. Thus, it may be much easier to
build  rather than merely maintain  muscle glycogen concentrations
when a pinch of high intensity is added to workouts, and for some athletes the
intensity may actually mean boosting glycogen levels back up to
performance-enhancing levels (if they have been slogging away for a while with
too-low levels of carbohydrate in their muscles). Note, too, how wonderfully
well the Australian plan would work for a marathon runner (or other endurance
athlete getting ready for a competition lasting longer than an hour). The
athlete could follow his normal diet during the week leading up to the race,
with no risk of bloating, lethargy, heaviness or gastric discomfort, and
training could be tapered appropriately. The day before the big race, he could
warm up, go hard for three minutes and then begin consuming
large quantities of carbs. He should feel great and have about 200 mmol.kg-1
wet weight in his leg muscles at the start line the following morning. He might
even find his overall running fitness inched up a notch. Worried about three
minutes of very hard
running the day before the marathon? Perhaps it might cause
your hamstrings to twitch a bit on race day? Dont worry: you can carry out the
24-hour plan two or even three days before your major event and still go to the
start line with supra-normal concentrations of glycogen in your muscles.
Research has shown that once such concentrations are achieved, they can be
maintained for a couple of days, providing athletes eat normal amounts of
carbohydrate and do not carry out much exercise. Since you will be tapering,
you wont be doing much exercise, so all should be well. Here, then, is your
guide to carbo-loading Aussie-style:

Start eating carbs as soon as possible
after you finish your exercise.

Consume high-glycaemic-index foods
during your 24-hour period, and dont be afraid to include high-carb
drinks like Polycose. Foods that count as high-glycaemic-index items (with
glycaemic-index values above 60) include the following: croissants, crumpets,
banana or apricot muffins, pancakes, waffles, scones, cranberry-juice cocktail,
Gatorade, bagels, baguettes, bread stuffing, oat bread, white bread, flatbread,
cornflakes, Pop Tarts, Raisin Bran, Special K, cornmeal, boiled sweet corn,
couscous, most crackers and crispbreads, rice cakes, chocolate ice cream,
apricots in syrup, dried dates, dried figs, papaya, raisins, watermelon, fruit
bars, a plain pizza with cheese and tomato sauce, kugel, gnocchi, udon noodles,
jelly beans, black-bean soup, split-pea soup, broad beans, parsnips, swede,
most baked potatoes (especially if baked without fat), most boiled potatoes,
mashed potatoes, and tapioca. Youll need to read box labels and use
nutritional charts to determine how much carbohydrate you are really taking in
during your 24-hour period; remember that you are aiming for about 4.6g of
carbohydrate per pound of body weight. If you fret about consuming
high-glycaemic-index foods, bear in mind that many of the foods consumed
heavily and regularly by élite Kenyan runners have very high glycaemic
indices. For example, maize-meal porridge checks in with a glycemic index of
109. (The standard glucose is set at 100, which means that maize-meal porridge
gets glucose into the bloodstream more quickly than glucose itself!) Another
popular Kenyan breakfast item millet-flour porridge has a similarly whopping
glycaemic index of 107. Kenyan rice a true staple of the Kenyan runners diet
has an eye-popping glycaemic index of 112, and cornmeal used to create the
ubiquitous Kenyan national dish, ugali, has an index of about 70. Kenyan
wholemeal wheat flour checks in at 87, and chapati, a flat wheat bread settles
for 66.

Once you have completed your warm-up,
three-minute burst and cool down, do not exercise again during the next 24
hours as this will damp down your muscles glycogen-synthesis
rate.

Dont be afraid of the lactate you
will inevitably generate during your three-minute surge. Remember that lactate
does you no harm; in fact, there is evidence that the lactate itself may spur
the increased rate of glycogen synthesis which occurs after intense
exercise.

The Aussie plan allows you to relax! If
work or other pressures have kept you from carbo-loading as much as you would
like before a major race, you can still do a tremendous job of stocking up on
muscle glycogen during the last 24 hours before your event.

Make sure you try out the Aussie regime
a couple of times in training before you use it in competition. (By trying it
out, I mean using the warm-up, three-minute burst, cool-down and 24-hour
carb-eating scheme, followed by a long run afterwards.) There should be no
major side effects associated with the plan, but you should at least prepare
your body for it. If the regime doesnt seem to be working well, try using
the 24-hour plan two days before your long workouts or races, while carrying
out little exercise and eating normally the day before the event. This
intervening day may allow you to recover from your three-minute blast, without
reducing your muscle glycogen concentrations.